The known system for cutting fabric, synthetic materials and leathers, can be classified in accordance with the cutting technique, providing for the use or non-use of die cutters, i.e. tools, having a cutting relief or edge forming a given shape, and cuts a material giving it the contour matching the cutting relief or edge.
Die cutting machines, which mount such cutter systems, known also as die cutting machines, are widespread in the industrial manufacturing field and use, as specified, cutting means, which are shaped according to the shape to be obtained, and which must be substituted for each new production lot (size changeover).
In time, the above systems have been substituted by the ones cutting without die cutters, which work with a continuous movement of a cutting tool along the contour of the piece to be obtained, applying a highly automated computer controlled process.
The use of this technology has many advantages, such as high production rate and cutting quality, a maximum reduction of scraps and the possibility to define dynamically the cutting contour, without the necessity to substitute the tool.
For example, FIG. 1 shows an automatic machine of known type, which applies the cutting system without die cutter and which is aimed at processing tanned leathers P of large dimensions.
In a horizontal work table L, supported by a structure S, a suction effect is produced by a plurality of holes made therein, not shown, connected to a source of vacuum, likewise not shown.
A beam support M can slide in a direction Y, parallel to the longitudinal axis H of the surface L, on two straight guides G1, G2, made at the lateral ends of the structure S.
Moreover, the beam support M bears a head T, carrying cutting tools and translating, sliding on relative guides, not shown, in a direction X, perpendicular to the direction Y.
Finally, a central unit C operates the beam support M and the head T, managing the cutting of the leathers P, placed in adherence onto the work table L, in accordance with the selected shape.
The extension of the work table L allows two big tanned leathers to be placed thereon (as seen in FIG. 1): in this way, the automatic machine can perform the cutting operations on a first leather P, placed in adherence onto a first part A of the surface L, while the operators spread a second leather P on the opposite part B, making sure that each portion of the leather adhere to the surface L, with the help of suction action performed by the vacuum source.
When the cutting operations on the first leather P are completed and the second leather P is placed completely in adherence on the surface L, the second leather P is cut and the operators pick up the scraps and the pieces obtained by cutting the first leather P, and then spread another leather.
Therefore, the processing of tanned leather, described in its significant steps, is cyclical and limited by the operators' manual operations, actually longer than the automatic cutting operations.
In fact, the spreading of a leather P on the work table L and the subsequent removal of the cutting products is very difficult, due to the limited access to some portions of the leather P, situated near the longitudinal axis H, which makes the operator climb up to the surface L or use a suitable structure.
A further limit to the production rate of the above machine derives from the quality control of the leathers to be cut, which requires looking for possible imperfections on the tanned leather, and subsequent marking of faulty areas.
This visual verify takes place by putting the leather on relative trestles or when the leather is already spread on the work table L.
Possible faulty areas, marked by the operator, will be rejected during the subsequent cutting operation.
At present, the production rate of similar machines is 4-5 leathers per hour.